Selecting a profile for an interface of a network device according to a margin

ABSTRACT

Selecting a profile for an interface of a network device includes accessing profile sequences, where each profile sequence corresponds to an interface. Each profile sequence includes profiles that provide parameters for communicating data. The following are repeated for a profile sequence for an interface until a link satisfies a sequence criterion or until a last profile of the profile sequence is reached to select a profile for the interface. A current profile is accessed, and a link for the interface is initiated according to the current profile. Whether the link for the interface satisfies the sequence criterion in accordance with the margin set is determined. A next profile of the profile sequence is accessed if the link does not satisfy the sequence criterion in accordance with the margin set, and the current profile is selected if the link satisfies the sequence criterion. Data is communicated according to the selected profile.

TECHNICAL FIELD OF THE INVENTION

This invention relates generally to the field of telecommunications andmore specifically to selecting a profile for an interface of a networkdevice according to a margin.

BACKGROUND OF THE INVENTION

Digital subscriber line (DSL) technologies such as very-high-data-ratedigital subscriber line (VDSL) technologies involve selection ofprofiles for communicating data between customer premises equipment anda network device. The selection may depend on, for example, the spectralenvironment available to the network device and the specific applicationfor which the equipment is used. Accordingly, selecting communicationprofiles may require skilled personnel to configure the equipment tooperate using selected profiles, assess the quality of the link acquiredat the selected profiles, and reconfigure the equipment to operate usingdifferent profiles if the quality of the link is unsatisfactory.Consequently, known techniques for selecting profiles for communicatingdata between customer premises equipment and a network device may beunsatisfactory in certain situations.

SUMMARY OF THE INVENTION

In accordance with the present invention, disadvantages and problemsassociated with previous techniques for selecting communication profilesmay be reduced or eliminated.

According to one embodiment of the invention, selecting a profile for aninterface of a network device includes accessing profile sequences,where each profile sequence corresponds to an interface. Each profilesequence includes profiles that provide parameters for communicatingdata. The following are repeated for a profile sequence for an interfaceuntil a link satisfies a sequence criterion or until a last profile ofthe profile sequence is reached to select a profile for the interface. Acurrent profile is accessed, and a link for the interface is initiatedaccording to the current profile. Whether the link for the interfacesatisfies the sequence criterion in accordance with the margin set isdetermined. A next profile of the profile sequence is accessed if thelink does not satisfy the sequence criterion in accordance with themargin set, and the current profile is selected if the link satisfiesthe sequence criterion. Data is communicated according to the selectedprofile.

Certain embodiments of the invention may provide one or more technicaladvantages. A technical advantage of one embodiment may be that anetwork device uses a profile sequence to establish a link between aninterface of the network device and customer premises equipment. Theprofile sequence comprises an ordered list of profiles, each of whichmay designate one or more rates at which data is to be communicatedbetween the customer premises equipment and the network device. Thenetwork device attempts to establish a satisfactory link according tothe ordered list of profiles to select a profile for communicating data.

Certain embodiments of the invention may include none, some, or all ofthe above technical advantages. One or more other technical advantagesmay be readily apparent to one skilled in the art from the figures,descriptions, and claims included herein.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention and itsfeatures and advantages, reference is now made to the followingdescription, taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 is a block diagram illustrating one embodiment of a system thatincludes a network device that selects profiles for interfaces of thenetwork device;

FIG. 2 is a block diagram illustrating one embodiment of the networkdevice of FIG. 1;

FIG. 3 is a flowchart illustrating one embodiment of a method forselecting a profile for an interface of a network device; and

FIG. 4 is a flowchart illustrating one embodiment of a method forselecting a profile for an interface of a network device according to amargin.

DETAILED DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention and its advantages are bestunderstood by referring to FIGS. 1 through 4 of the drawings, likenumerals being used for like and corresponding parts of the variousdrawings.

FIG. 1 is a block diagram illustrating one embodiment of a system 10that includes a network device that selects profiles for the interfacesof the network device. The profiles provide parameters according towhich network device communicates data to and from customer premisesequipment. The network device determines profiles for each interface ofthe network device. “Each” as used in this document refers to eachmember of a set or each member of a subset of the set.

According to the illustrated embodiment, system 10 includes customerpremises equipment 20 a-b, plain old telephone service (POTS) splitters22 a-b, a private branch exchange (PBX) 23, a public switched telephonenetwork (PSTN) 25, a network device 24, a communication network 26, anda computer system 54 coupled as illustrated in FIG. 1. Customer premisesequipment 20 a-b comprises communication equipment that resides at theend user's premises that is suitable for communicating with networkdevice 24, which is typically not at the end user's premises. Customerpremises equipment 20 a-b typically resides at a customer's premises butcould reside anywhere.

Communication equipment may include, for example, a voice device, a datadevice, or any combination of the preceding. A voice device may include,for example, a telephone, a fax machine, or any other equipment suitablefor connecting to PBX 23, PSTN 25, or customer premises equipment 20a-b. A data device may include, for example, a computer, an IPtelephone, or any other data device suitable for connecting to switch24, computer system 54, or communications network 26. Premises maycomprise, for example, an office, a factory, a residence, or any otherlocation where communication equipment may be located.

Customer premises equipment 20 a-b combines signals received fromdevices such as a voice device and a data device, and communicates thecombined signal to POTS splitter 22 a-b and switch 24. The signals maybe distributed according to frequency. For example, the voice signal mayhave a frequency of approximately 0.3 kilohertz to 4 kilohertz, and thedata signal may have a frequency of approximately 25 kilohertz to 12megahertz. POTS splitter 22 a-b splits signals received from customerpremises equipment 22 a-b into a voice signal and a data signal. Voicesignals are communicated to PBX 23, and data signals are communicated toswitch 24. PBX 23 communicates voice signals between POTS splitters 22a-b and PSTN 25.

Network device 24 communicates data from customer premises equipment 20a-b to communications network 26, and communicates data fromcommunications network 26 to the appropriate customer premises equipment20 a-b. Network device 24 includes interfaces that are used tocommunicate with customer premises equipment 20 a-b. Examples of networkdevice 24 include a switch, a router, or other device operable tocommunicate signals. Network device 24 includes interfaces that are usedto communicate with customer premises equipment 20 a-b. According to oneembodiment, network device 24 operates according to a digital subscriberlink (DSL) technology such as a very-high-data-rate digital subscriberline (VDSL) technology. Network device 24 is described in more detailwith reference to FIG. 2.

For each interface, network device 24 selects a profile sequence thatincludes profiles according to which the interface communicates withcustomer premises equipment 20 a-b. Each profile may specify, forexample, a rate set, which may include an upstream rate forcommunicating data from customer premises equipment 20 a-b to networkdevice 24 and a downstream rate for communicating data from networkdevice 24 to customer premises equipment 20 a-b. A method for selectinga profile is described in more detail with reference to FIG. 3.According to one embodiment, a profile may be associated with a margincomprising, for example, a measure of a link established according tothe profile such as a signal-to-noise-ratio value or a Reed-Solomonerror. A link may be designated as acceptable only if the link satisfiesthe margin. A method for selecting a profile according to a margin isdescribed in more detail with reference to FIG. 4.

A rate set designates, among other things, a power spectral density foran interface. The power spectral density represents the amount of powerthat is applied to a range of the spectrum over a link in order toachieve a satisfactory level of signal strength at the receiving end ofthe link, and is typically measured in dBm per Hertz. A rate set alsomay include designations for bits per symbol, interpolation settings,interleaver or latency settings, and may include these per band used,and may include these for downstream communication, upstreamcommunication, or both. The power spectral density according to which alink may be satisfactorily established is determined in part by theenvironment, which may be determined by, for example, type of cable,condition of cable, length of cable, existence of bridge taps, thepresence of interferers such as near-end and far-end crosstalk, or anysource of radiation emitted in the frequencies used by the system.Because the environment may include many factors, the appropriate powerspectral density may be difficult to predict.

Computer system 54 may be used to provide commands to and receivereports from network device 24. Computer system 54 may includeappropriate input devices, output devices, mass storage media,processors, computer system memory, or other components for receiving,processing, storing, and communicating information according to theoperation of system 10. As used in this document, the term “computer”refers to any suitable device operable to accept input, process theinput according to predefined rules, and produce output, for example, apersonal computer, work station, network computer, wireless telephone,personal digital assistant, one or more microprocessors within these orother devices, or any other suitable processing device.

Communication network 26 allows customer premises equipment 20 a-b tocommunicate with other networks or devices. Communication network 26 maycomprise a public switched telephone network (PSTN), a public or privatedata network, the Internet, a wired or wireless network, a local,regional, or global communication network, an enterprise internet, othersuitable communication link, or any combination of the preceding.

Modifications, additions, or omissions may be made to system 10 withoutdeparting from the scope of the invention. For example, although system10 is illustrated as having two pieces of customer premises equipment 20a-b, system 10 may include any suitable number of pieces of customerpremises equipment 20 a-b. As another example, POTS splitter 22 a-b maybe included at customer premises equipment 20 a-b or at network device24, or may be omitted. Additionally, functions may be performed usingany suitable logic comprising software, hardware, other logic, or anysuitable combination of the preceding.

FIG. 2 is a block diagram illustrating one embodiment of network device24 of system 10. Network device 24 uses a profile sequence in order toselect profiles at which network device 24 communicates with customerpremises equipment 20 a-b. According to one embodiment, network device24 operates according to a digital subscriber link (DSL) technology suchas a very-high-data-rate digital subscriber line (VDSL) technology.

According to the illustrated embodiment, network device 24 includesinterfaces 40 and 41, a processor 42, applications 46, a memory 48, atimer 50, and a report generator 52 coupled as illustrated in FIG. 2.Interfaces 40 communicate data to and from customer premises equipment20 a-b. An interface 40 may comprise any suitable link for couplingnetwork device 24 to customer premises equipment 20 a-b such as a port.According to one embodiment, one interface may communicate with onecustomer premises equipment 20. Interfaces 40, however, may beconfigured with customer premises equipment 20 a-b according to anysuitable arrangement.

Processor 42 manages the operations of network device 24. Processor 42comprises any suitable device operable to accept input, process theinput according to predefined rules, and produce an output. Applications46 provide instructions for processor 42. Interface 41 communicates databetween network device 24 and communications network 26 and betweennetwork device 24 and computer system 54.

Memory 48 includes profiles 60, margins 61, and a sequence table 62.Profiles 60 specify how network device 24 communicates with customerpremises equipment 20 a-b, for example, how upstream and downstream dataare communicated.

For example, profiles 60 may specify one or more downstream bands, oneor more upstream bands, an interleaver depth, a transmit power, notchfilter frequencies, or a preamble pattern. Each of the upstream bandsand downstream bands may include one or more bands assigned to aspecific direction. Each band may be defined as having attributes suchas a carrier frequency, constellation (designated in bits per symbol),analog bandwidth, interleaver depth (which may also specify the latencyof the data passed in this band), maximum transmit power, minimumtransmit power, notch filter (which may include zero or more frequenciesfor which the transmit power is attenuated), transmit preamble pattern,or receive preamble pattern template. The analog bandwidth, inconjunction with the carrier frequency, may determine the lowestfrequency and highest frequency used by the band. The constellation andanalog bandwidth together may determine the data rate for the band.

Profiles 60 may specify these and other characteristics for the upstreamchannel, the downstream channel, or both. Profiles 60 may also specifyany number of other or additional parameters specific to the transporttechnology being employed.

According to one embodiment, each profile 60 may comprise a rate setthat designates rates for communicating data. For example, a rate setmay comprise an upstream rate specifying a rate for upstreamcommunication and a downstream rate specifying a rate for downstreamcommunication.

A profile 60 may also designate, for example, a center frequency and abandwidth range of frequencies about the center frequency with whichdata is to be communicated. For example, according to an embodimentusing two band VDSL, the frequency of the downstream band is lower thanthe frequency of the upstream band. A profile 60 may specify that thedownstream band communicates with a center frequency of approximately1.831 megahertz with a 1.3 megahertz bandwidth, and that the upstreamband communicates with a center frequency of approximately 4.467megahertz with a 970 kilohertz bandwidth.

TABLE 1 illustrates example profiles 60 that specify example dowmstreamrates and upstream rates.

TABLE 1 Downstream Upstream Rate Profile Name Rate (Mbps) (Mbps) LRE-1516.667 18.750 LRE-15-5 16.667 6.250 LRE-15-3 16.667 3.125 LRE-15-116.667 1.563 LRE-10 12.500 12.500 LRE-10-5 12.500 6.250 LRE-10-3 12.5003.125 LRE-10-1 12.500 1.563 LRE-8 9.375 9.375 LRE-7 8.333 8.333 LRE-56.250 6.250 LRE-4 4.167 4.167 LRE-4-1 4.167 1.563 LRE-3 3.125 3.125LRE-2 2.083 2.083Each profile 60 of TABLE 1 includes an upstream rate and a downstreamrate. For example, profile LRE-15 includes an upstream rate of 16.667megabits per second and a downstream rate of 18.750 megabits per second.

Profiles 60 may be ordered to form a profile sequence by choosing theprofiles from an ordered list. For example, a profile sequence maycomprise an ordered sequence of LRE-15, LRE-10, LRE-8, and LRE-4. Aprofile sequence designates the order of profiles at which networkdevice 24 attempts to establish a link at an interface 60. The order maybe system defined or user defined. A sequence criterion associated witha profile sequence specifies whether a link is satisfactory such that anext profile of the profile sequence does not need to be selected toattempt a next link. For example, a link may be satisfactory if it isestablished.

The profiles 60 of a profile sequence may be chosen according to anysuitable selection procedure to yield any suitable order that allowsnetwork device 24 to determine a profile 60 for an interface. Forexample, the profiles 60 may be selected according to a top-downselection procedure such that network device 24 first attempts toestablish a link at the fastest rate. If the link cannot be established,the link may be designated as not satisfactory, so network device 24attempts to establish a link at the next faster rate, and so on, until alink is established. As another example, the profiles 60 may be selectedaccording to a bottom-up selection procedure such that network device 24first attempts to establish a link at the slowest rate. If the link isestablished but too slow, the link may be designated as notsatisfactory. Network device 24 may attempt to establish a link at thenext slowest rate, and so on, until a link cannot be established todetermine the fastest rate at which the link may be established.

As yet another example, the profiles 60 may be selected according to abinary selection procedure of the rates 60. The first profile maycomprise a median rate set that divides the profiles into a set offaster profiles with faster rate sets and a set of slower profiles withslower rate sets. If the link is established, the next profile is theprofile with the median rate set of the faster profiles. If the link isnot established, the next profile is the profile with the median rateset of the slower profiles.

A faster rate may refer to a faster upstream rate, a faster downstreamrate, a faster symmetric rate, or a faster aggregate rate comprising thesum of the upstream rate and the downstream rate. A slower rate mayrefer to a slower upstream rate, a slower downstream rate, a slowersymmetric rate, or a slower aggregate rate comprising the sum of theupstream rate and the downstream rate.

Other criteria for selection may include threshold criteria,latency-based criteria, interleaver-depth-based criteria, bandplan-basedcriteria, constellation-based criteria, analog bandwidth-based criteria,notch-filter-based criteria, other suitable criteria, or any combinationof the preceding.

Threshold criteria may include, for example, a downstream ceiling,upstream ceiling, downstream floor, or upstream floor. Latency-basedcriteria may include, for example, lowest downstream latency, lowestupstream latency, downstream latency ceiling, upstream latency ceiling,downstream latency floor, or upstream latency floor.Interleaver-depth-based criteria may include, for example, deepestdownstream interleaver, deepest upstream interleaver, downstreaminterleaver depth ceiling, upstream interleaver depth ceiling,downstream interleaver depth floor, or upstream interleaver depth floor.

Bandplan-based criteria involves ordering profiles based on thebandplans with which the profiles comply. Bandplan-based criteria mayinclude, for example, Plan 998, Plan 997, Plan C, Plan China, or PlanUser Defined. Constellation-based criteria may include, for example,lowest downstream constellation, highest downstream constellation,lowest upstream constellation, highest upstream constellation, lowestaggregate constellation upstream and downstream, or highest aggregateconstellation upstream and downstream.

Analog bandwidth-based criteria may include, for example, lowestdownstream bandwidth, lowest upstream bandwidth, highest downstreambandwidth, highest upstream bandwidth, lowest downstream low frequency,lowest upstream low frequency, highest downstream low frequency, highestupstream low frequency, lowest downstream high frequency, lowestupstream high frequency, highest downstream high frequency, highestupstream high frequency, lowest downstream carrier frequency, highestdownstream carrier frequency, lowest upstream carrier frequency, orhighest upstream carrier frequency. Notch-filter-based criteria mayinclude, for example, notch at frequency X or notches at frequency X+Xn.

Multiple criteria may include, for example, burst-noise protection (afunction of the rate and the interleaver depth/latency), rates (usingprimary and secondary ordering of rate preferences), any collection ofprofile ordering where preferences are combined (for example, highestdownstream rate and meets bandplan 997, while having notches atfrequency X and using lowest downstream constellation and the highestdownstream analog bandwidth), or multiple criteria with variableweighting.

Margins 61 may be used to assess the acceptability of a link establishedat certain profiles. Margins 61 may comprise, for example, asignal-to-noise-ratio (SNR), quantity of Reed-Solomon errors per unittime, receive power, automatic gain control gain, or actual transmitpower. The actual transmit power used to maintain a link with otheracceptable properties may be defined as X dB below a maximum allowabletransmit power and Y dB above a minimum allowable transmit power toallow for sufficient headroom to modulate transmit power for otherpurposes. According to one embodiment, a margin 61 comprises asignal-to-noise ratio margin that represents the range above atheoretical signal-to-noise ratio minimum that an actual signal-to-noiseratio of a link should satisfy in order to be designated as acceptable.For example, if the theoretical signal-to-noise ratio minimum is 25decibels and if the margin is three decibels, then the established linkshould have an actual signal-to-noise ratio of at least 28 decibels tobe designated as acceptable.

The signal-to-noise ratio margin may have any suitable value, forexample, the margins may be in a range of zero to ten decibels. Theselection of a margin 61 may depend on a required bit-error ratio or anoise level of the environment. A lower bit-error ratio typicallyrequires a higher signal-to-noise ratio. A noisier environment typicallyrequires a higher signal-to-noise ratio. For example, a margin of twodecibels may be used for a low noise environment, a margin of fourdecibels may be used for a medium noise environment, and a margin of sixdecibels may be used for a high noise environment.

Margins 61 may be selected for each rate of a rate set. For example, anupstream margin may be associated with an upstream rate and a downstreammargin may be associated with a downstream rate. According to oneembodiment, both upstream and downstream margins must be satisfied.Other embodiments, however, may require that only the downstream marginsor only the upstream margins need to be satisfied.

TABLE 2 illustrates examples of margins 61 comprising signal-to-noiseratios for downstream rates.

TABLE 2 Low Medium High Noise Noise Noise Profile Downstream TheoreticalSNR SNR SNR Name Rate QAM Min SNR (dB) (dB) (dB) (dB) LRE-4-1 4.17 16 2224 26 29 LRE-5 6.25 8 19 21 23 26 LRE-10 12.5 64 25 27 29 32 LRE-1516.667 256 31 33 35 39 LRE-10-5 12.5 64 25 27 29 32 LRE-10-3 LRE-10-1Public- 16.667 256 31 33 35 39 ANSI Public- 12.5 256 31 33 35 39 ETSILRE-2 2.08 4 13 15 17 20 LRE-3 3.13 4 13 15 17 20 LRE-4 4.17 4 13 15 1720Different signal-to-noise ratios of TABLE 2 are specified for differentamounts of noise. For example, for profile LRE-5, the low noisesignal-to-noise ratio is 21 decibels, the medium noise signal-to-noiseratio is 23 decibels, and the high noise signal-to-noise ratio is 26decibels. A default profile may be set at, for example, LRE-4-1.

TABLE 3 illustrates examples of margins 61 comprising signal-to-noiseratios for upstream rates.

TABLE 3 Low Medium High Noise Noise Noise Profile Upstream TheoreticalSNR SNR SNR Name Rate QAM Min SNR (dB) (dB) (dB) (dB) LRE-4-1 1.56 4 1315 17 20 LRE-5 6.25 4 13 15 17 20 LRE-10 12.5 16 19 21 23 26 LRE-1518.75 64 25 27 30 34 LRE-10-5 6.25 4 13 15 17 20 LRE-10-3 3.125 16 19 2123 26 LRE-10-1 1.56 4 13 15 17 20 Public- 4.688 64 25 27 29 32 ANSIPublic- 4.688 64 25 27 29 32 ETSI LRE-2 2.08 4 13 15 17 20 LRE-3 3.13 413 15 17 20 LRE-4 4.17 4 13 15 17 20As illustrated in TABLE 3, different signal-to-noise ratios arespecified for different noise levels. For example, for profile LRE-5,the low noise signal-to-noise ratio is 15 decibels, the medium noisesignal-to-noise ratio is 17 decibels, and the high noise signal-to-noiseratio is 20 decibels. A default profile may be set at, for example,LRE-4-1.

Sequence table 62 is used to assign a sequence profile and an associatedmargin 61 to an interface 40. According to one embodiment, a profilesequence is assigned to each interface 40. A profile sequence, however,may be assigned to a set of interfaces 40 or to all interfaces 40 ofnetwork device 24. Additionally, some interfaces 40 of network device 24may not have assigned profile sequences. For such interfaces 40, networkdevice 24 may establish links at an assigned or a default profile.

Sequence table 62 may also indicate whether an interface 40 has a lockedprofile. Network device 24 may select a profile 60 for an interface 40and then lock the selected profile 60 for the interface 40. In the eventthat network device 24 may need to perform profile selection for otherinterfaces 40, network device may revert back to the locked profileinstead of performing profile selection for the interface 40.

Network device 24 may select a profile for an interface 40 according toany of a number of different processes. As discussed above, the profilemay be selected according to a profile sequence assigned to interface40, to a set of interfaces 40 that include interface 40, or to a globalset of interfaces 40 of network device 24. Alternatively, the profilemay be set by a profile assigned to interface 40, to a set of interfaces40 to which interface 40 belongs, or to the global set of interfaces 40of network device 24. The processes may be prioritized. For example, aprofile assigned to interface 40 may take precedence over a globalprofile, and a sequence assigned to interface 40 may take precedenceover a global sequence.

Timer 50 may include a watchdog timer that measures the duration that ittakes for network device 24 to establish a link according to a profile60. The watchdog timer may be set to any suitable duration, for example,approximately 30 seconds. Timer 50 may also measure the convergencetime, which represents the amount of time network device 24 takes toselect an appropriate profile 60. A suitable convergence time may be,for example, approximately less than two minutes. If a profile 60 is notselected within a suitable convergence time, network device 24 mayselect a default profile for the interface 40. The convergence time maybe decreased by decreasing the duration of the watchdog timer. Theconvergence time may also be decreased by decreasing the number ofprofiles 60 of a profile sequence.

Report generator 52 generates reports describing the profiles for eachinterface 40, and may output reports through computer system 54. Areport may describe the configured profile of a link that has beenestablished at interface 40, the running profile of a link that networkdevice 24 is attempting to establish at interface 40, or the type ofprofile assigned to interface 40. The type of profile may comprise, forexample, a global profile, which is a single profile that is applied toall interfaces 40, an interface profile, a global sequence, which is asingle profile sequence that is applied to all interfaces 40, or aninterface sequence.

Modifications, additions, or omissions may be made to network device 24without departing from the scope of the invention. For example, margins61 are discussed as comprising signal-to-noise ratios. Margins 61,however, may comprise any suitable measure of link quality.Additionally, functions may be performed using any suitable logiccomprising software, hardware, other logic, or any suitable combinationof the preceding.

FIG. 3 is a flowchart illustrating one embodiment of a method forselecting a profile for an interface 40 of network device 24. The methodmay be executed at the occurrence of an event that signals that profilesare to be selected for interfaces 40. Events may include, for example,adding a new piece of customer premises equipment 20, losing a link formore than a specified period of time such as 25 seconds, determiningthat the health of a link falls below a threshold value, receiving anexecution command to restart profile selection, or receiving a boot upcommand. Other events may include, for example, boot-up time, reset,time of link up, user demand time, loss of specified margin, or Xoccurrences of loss of margin occurring within time period Y.Alternatively, network device 24 may revert to a locked profile in placeof executing the profile selection method. The method may also beautomatically run periodically, such as once every day, week, or othertime interval.

The method begins at 110, where system 10 is initialized. Systeminitialization may include initialization of profile selectionstructures such as sequence table 62. The system configuration may alsobe processed as part of the system initialization. Duringinitialization, a default profile may be applied to interfaces 40.

An interface 40 is selected at step 112. Network device 24 determineswhether there is a profile sequence assigned to interface 40 by sequencetable 62 at step 114. If there is no profile sequence assigned tointerface 40, the method proceeds to step 115, where network device 24determines whether a profile has been configured for interface 40. If aprofile has been configured, the method proceeds to step 117, where theconfigured profile is selected. Network device 24 attempts to establisha link and communicate data according to the selected profile at step121, and then proceeds to step 136. If a profile has not beenconfigured, the method proceeds to step 116, where interface 40 selectsthe default profile, and the method proceeds to step 121.

If there is a profile sequence assigned to interface 40 at step 114, themethod proceeds to step 118, where network device 24 determines whetherinterface 40 has a locked profile. If interface 40 has a locked profile,the method proceeds to step 120, where the locked profile is selected,and the method proceeds to step 121.

If interface 40 does not have a locked profile at step 118, the methodproceeds to step 122, where a profile is selected from the profilesequence assigned to interface 40. The profile sequence includes anordered sequence of profiles. At each iteration of the method, a profileis selected in accordance with the order. The selected profile isapplied at step 124. The selected profile may include a rate set havingan upstream rate and a downstream rate, and may be applied by initiatinga link that communicates upstream data according to the upstream rateand that communicates downstream data according to the downstream rate.

Timer 50 is started at step 126. Network device 24 determines whether alink is satisfactory, for example, has been established at step 128. Ifthe link has not been established, the method proceeds to step 130,where network device 24 determines whether timer 50 has expired. Iftimer 50 has not expired, the method returns to step 128, where networkdevice 24 determines whether a link has been established. If timer 50has expired, the method proceeds to step 134, where network device 24determines whether there is a next profile of a profile sequence that isto be selected. If there is a next profile, the method returns to step122 to select the next profile from the profile sequence. If there is nonext profile, the method proceeds to step 132, where network device 24reverts to the last profile that could be used to establish a link. Themethod then proceeds to step 135, where network device 24 communicatesdata across the established link. The method then proceeds to step 136.If a link has been established at step 128, the method proceeds directlyto step 135.

At step 136, network device 24 determines whether there is a nextinterface 40 for which a profile may be selected. If there is a nextinterface 40, the method returns to step 112, where the next interface40 is selected. If there is no next interface, the method terminates.

Modifications, additions, or omissions may be made to the method withoutdeparting from the scope of the invention. For example, network device24 does not necessarily require the ability to lock a profile.Accordingly, determining whether there is a locked profile at step 118does not need to be performed. Additionally, steps may be performed inany suitable order without departing from the scope of the invention.For example, starting timer 50 at step 126 may be performed prior toapplying the profile at step 124.

FIG. 4 is a flowchart illustrating one embodiment of a method forselecting a profile for an interface 40 of network device 24 accordingto a margin. The method begins at step 210, where system 10 isinitialized. An interface 40 is selected at step 212. A profile sequenceassigned to interface 40 by sequence table 62 is accessed at step 214. Aprofile is selected from the profile sequence at step 216.

The selected profile is applied at step 218 to initialize a link.Network device 24 determines whether a link is satisfactory, forexample, has been established at step 220. If a link is not established,the method proceeds to step 224, where network device determines ifthere is a next profile of the profile sequence to be selected. If thereis a next profile, the method returns to step 216 to select the nextprofile. If there is no next profile, the method proceeds to step 222,where system 24 reverts to a previous profile according to which a linkwas established, for example, a default profile. The method thenproceeds to step 234. If a link is established at step 220, the methodproceeds to step 226.

Network device 24 accesses a required margin associated with the profilefrom sequence table 62 at step 226. According to one embodiment, themargin may comprise a signal-to-noise ratio margin. The signal-to-noiseratio margin may be added to a theoretical signal-to-noise ratio tocalculate a minimum signal-to-noise ratio that the link must satisfy. Alink quality is determined at step 228. For example, the actualsignal-to-noise ratio of the link may be measured.

Network device 24 determines whether the link satisfies the requiredmargin at step 230. For example, the link satisfies the margin if theactual signal-to-noise ratio of the link measured at step 228 is greaterthan the minimum signal-to-noise ratio described at step 226. If therequired margin is not satisfied, the method proceeds to step 224. Ifthe required margin is satisfied, the method proceeds to step 232, wherenetwork device 24 communicates data according to the selected profile.The method then proceeds to step 234. At step 234, network device 24determines if there is a next interface 40 for which a profile is to beselected. If there is a next interface 40, the method returns to step212 to select the next interface 40. If there is no next interface 40,the method terminates.

Modifications, additions, or omissions may be made to the method withoutdeparting from the scope of the invention. Additionally, steps may beperformed in any suitable order without departing from the scope of theinvention.

Certain embodiments of the invention may provide one or more technicaladvantages. A technical advantage of one embodiment may be that anetwork device uses a profile sequence to establish a link between aninterface of the network device and customer premises equipment. Theprofile sequence comprises an ordered list of profiles, each of whichdesignates one or more profiles at which data is to be communicatedbetween the customer premises equipment and the network device. Thenetwork device attempts to establish a satisfactory link according tothe ordered list of profiles to select a profile for communicating data.

Although an embodiment of the invention and its advantages are describedin detail, a person skilled in the art could make various alterations,additions, and omissions without departing from the spirit and scope ofthe present invention as defined by the appended claims.

1. A method for selecting a profile for an interface of a networkdevice, comprising: accessing a plurality of profile sequencesassociated with a network device comprising a plurality of interfaces,each profile sequence corresponding to an interface, each profilesequence comprising a plurality of profiles, each profile providing atleast one parameter for communicating data, each profile associated witha margin set comprising one or more margins; repeating the following fora profile sequence corresponding to an interface until a link satisfiesa sequence criterion or until a last profile of the profile sequence isreached in order to select a profile for the interface: accessing acurrent profile, the current profile associated with a margin set;initiating a link for the interface according to the current profile;determining if the link for the interface satisfies the sequencecriterion in accordance with the margin set; accessing a next profile ofthe profile sequence if the link does not satisfy the sequence criterionin accordance with the margin set; and selecting the current profile ifthe link satisfies the sequence criterion in accordance with the marginset; and communicating data using the link according to the selectedprofile.
 2. The method of claim 1, wherein a profile comprises a memberselected from a group consisting of a downstream band, an upstream band,an interleaver depth, a transmit power, a notch filter frequency, and apreamble pattern.
 3. The method of claim 1, wherein each margin setcomprises a margin selected from a group consisting of asignal-to-noise-ratio, a quantity of Reed-Solomon errors per unit time,a receive power, an automatic gain control gain, and an actual transmitpower.
 4. The method of claim 1, wherein: each profile comprises aparameter selected from a group consisting of an upstream parameter anda downstream parameter; and each margin set comprises a margin selectedfrom a group consisting of an upstream margin and a downstream margin,the upstream parameter associated with the upstream margin, thedownstream parameter associated with the downstream margin.
 5. Themethod of claim 1, wherein determining if the link for the interfacesatisfies the sequence criterion in accordance with the margin setcomprises: establishing the margin set associated with the profile, themargin set comprising a link criterion for a link; determining ameasurement corresponding the link; and determining if the measurementsatisfies the link criterion.
 6. The method of claim 1, furthercomprising communicating the data at a default profile if the link isnot established at any profile of the profile sequence.
 7. An apparatusfor selecting a rate for an interface of a network device, comprising: amemory operable to store a plurality of profile sequences associatedwith a network device comprising a plurality of interfaces, each profilesequence corresponding to an interface, each profile sequence comprisinga plurality of profiles, each profile providing at least one parameterfor communicating data, each profile associated with a margin setcomprising one or more margins; and a processor coupled to the memoryand operable to: repeat the following for a profile sequencecorresponding to an interface until a link satisfies a sequencecriterion or until a last profile of the profile sequence is reached inorder to select a profile for the interface: access a current profile,the current profile associated with a margin set; initiate a link forthe interface according to the current profile; determine if the linkfor the interface satisfies the sequence criterion in accordance withthe margin set; access a next profile of the profile sequence if thelink does not satisfy the sequence criterion in accordance with themargin set; and select the current profile if the link satisfies thesequence criterion in accordance with the margin set; and communicatedata using the link according to the selected profile.
 8. The apparatusof claim 7, wherein a profile comprises a member selected from a groupconsisting of a downstream band, an upstream band, an interleaver depth,a transmit power, a notch filter frequency, and a preamble pattern. 9.The apparatus of claim 7, wherein each margin set comprises a marginselected from a group consisting of a signal-to-noise-ratio, a quantityof Reed-Solomon errors per unit time, a receive power, an automatic gaincontrol gain, and an actual transmit power.
 10. The apparatus of claim7, wherein: each profile comprises a parameter selected from a groupconsisting of an upstream parameter and a downstream parameter; and eachmargin set comprises a margin selected from a group consisting of anupstream margin and a downstream margin, the upstream parameterassociated with the upstream margin, the downstream parameter associatedwith the downstream margin.
 11. The apparatus of claim 7, wherein theprocessor is operable to determine if the link for the interfacesatisfies the sequence criterion in accordance with the margin set by:establishing the margin set associated with the profile, the margin setcomprising a link criterion of a link; determining a measurementcorresponding the link; and determining if the measurement satisfies thelink criterion.
 12. The apparatus of claim 7, wherein the processor isfurther operable to communicate the data at a default profile if thelink is not established at any profile of the profile sequence.
 13. Acomputer-readable medium having computer-executable instructions forselecting a rate for an interface of a network device, when executed bya computer operable to: access a plurality of profile sequencesassociated with a network device comprising a plurality of interfaces,each profile sequence corresponding to an interface, each profilesequence comprising a plurality of profiles, each profile providing atleast one parameter for communicating data, each profile associated witha margin set comprising one or more margins; repeat the following for aprofile sequence corresponding to an interface until a link satisfies asequence criterion or until a last profile of the profile sequence isreached in order to select a profile for the interface: access a currentprofile, the current profile associated with a margin set; initiate alink for the interface according to the current profile; determine ifthe link for the interface satisfies the sequence criterion inaccordance with the margin set; access a next profile of the profilesequence if the link does not satisfy the sequence criterion inaccordance with the margin set; and select the current profile if thelink satisfies the sequence criterion in accordance with the margin set;and communicate data using the link according to the selected profile.14. The computer-readable medium of claim 13, wherein a profilecomprises a member selected from a group consisting of a downstreamband, an upstream band, an interleaver depth, a transmit power, a notchfilter frequency, and a preamble pattern.
 15. The computer-readablemedium of claim 13, wherein each margin set comprises a margin selectedfrom a group consisting of a signal-to-noise-ratio, a quantity ofReed-Solomon errors per unit time, a receive power, an automatic gaincontrol gain, and an actual transmit power.
 16. The computer-readablemedium of claim 13, wherein: each profile comprises a parameter selectedfrom a group consisting of an upstream parameter and a downstreamparameter; and each margin set comprises a margin selected from a groupconsisting of an upstream margin and a downstream margin, the upstreamparameter associated with the upstream margin, the downstream parameterassociated with the downstream margin.
 17. The computer-readable mediumof claim 13, when executed by the computer further operable to determineif the link for the interface satisfies the sequence criterion inaccordance with the margin set by: establishing the margin setassociated with the profile, the margin set comprising a link criterionof a link; determining a measurement corresponding the link; anddetermining if the measurement satisfies the link criterion.
 18. Thecomputer-readable medium of claim 13, when executed by the computerfurther operable to communicate the data at a default profile if thelink is not established at any profile of the profile sequence.
 19. Asystem for selecting a rate for an interface of a network device,comprising: means for accessing a plurality of profile sequencesassociated with a network device comprising a plurality of interfaces,each profile sequence corresponding to an interface, each profilesequence comprising a plurality of profiles, each profile providing atleast one parameter for communicating data, each profile associated witha margin set comprising one or more margins; means for repeating thefollowing for a profile sequence corresponding to an interface until alink satisfies a sequence criterion or until a last profile of theprofile sequence is reached in order to select a profile for theinterface: accessing a current profile, the current profile associatedwith a margin set; initiating a link for the interface according to thecurrent profile; determining if the link for the interface satisfies thesequence criterion in accordance with the margin set; accessing a nextprofile of the profile sequence if the link does not satisfy thesequence criterion in accordance with the margin set; and selecting thecurrent profile if the link satisfies the sequence criterion inaccordance with the margin set; and means for communicating data usingthe link according to the selected profile.
 20. A method for selecting aprofile for an interface of a network device, comprising: accessing aplurality of profile sequences associated with a network devicecomprising a plurality of interfaces, each profile sequencecorresponding to an interface, each profile sequence comprising aplurality of profiles, each profile providing at least one parameter forcommunicating data, a profile comprising a member selected from a groupconsisting of a downstream band, an upstream band, an interleaver depth,a transmit power, a notch filter frequency, and a preamble pattern, eachprofile associated with a margin set comprising one or more margins,each margin set comprising a margin selected from a group consisting ofa signal-to-noise-ratio, a quantity of Reed-Solomon errors per unittime, a receive power, an automatic gain control gain, and an actualtransmit power, each profile comprising a parameter selected from agroup consisting of an upstream parameter and a downstream parameter,each margin set comprising a margin selected from a group consisting ofan upstream margin and a downstream margin, the upstream parameterassociated with the upstream margin, the downstream parameter associatedwith the downstream margin; repeating the following for a profilesequence corresponding to an interface until a link satisfies a sequencecriterion or until a last profile of the profile sequence is reached inorder to select a profile for the interface: accessing a currentprofile, the current profile associated with a margin set; initiating alink for the interface according to the current profile; determining ifthe link for the interface satisfies the sequence criterion inaccordance with the margin set by establishing the margin set associatedwith the profile, the margin set comprising a link criterion of a link,by determining a measurement corresponding the link, and by determiningif the measurement satisfies the link criterion; accessing a nextprofile of the profile sequence if the link does not satisfy thesequence criterion in accordance with the margin set; and selecting thecurrent profile if the link satisfies the sequence criterion inaccordance with the margin set; communicating data using the linkaccording to the selected profile; and communicating the data at adefault profile if the link is not established at any profile of theprofile sequence.